Inflammtory Bowel Disease — New Directions for Future Research

Abstract

The etiology and the pathogenesis of ulcerative colitis and Crohn’s disease of the small and/or large intestine remain obscure, despite the increasing familiarity with these disorders. The similar clinical features and course of IBD everywhere in the world, despite differing ethnic populations, environmental circumstances, dietary habits and socio-cultural customs and the rising incidence of Crohn’s disease, apparently world-wide, suggests the involvement of environmental agents (microbial, dietary, pollutants, etc.). Attempts to clarify the nature of ulcerative colitis and Crohn’s disease on the basis of discernible tissue and cellular reactions, as determined by light, scanning and electron microscopy and histochemical and immunological reactions are informative and undoubtedly significant, but their interpretation is limited by questions as to the constancy and specificity of the observed changes, by the influences of anti-bacterial, adrenocortical steroids and other therapeutic agents, nutritional state, by individual differences in host response, and by the likelihood that both the small and the large intestine have a limited repertoire of tissue responses regard-less of the inciting etiologic mechanism. Multiple granulomas in the resected bowel wall and rectal biopsies are helpful in the diagnosis of Crohn’s disease, but are absent in 40% of patients; and, once present, they may disappear; their pathogenetic significance remains unclear, but probably is limited.